The invention relates to confocal microscopes.
Confocal microscopy involves focusing and scanning light at a sample plane in order to form a high-resolution, highly magnified image. Conventional confocal microscopes image samples by generating a series of thin "optical sections" which are high-resolution images of thin planes within the sample (see, e.g., U.S. Pat. Nos. 4,827,125; 4,198,571, the contents of which are incorporated herein by reference). Confocal microscopy usually is done in vitro.
There are two conventional types of confocal scanning microscopes. The tandem scanning confocal microscope ("TSCM") employs a rotating pinhole disk illuminated by a light source such as a mercury lamp. During operation, the disk sweeps a focal spot through a sample, and is additionally used to spatially filter back-scattered light. This instrument has been used, for example, to image sections of skin. A similar device, the confocal laser scanning microscope ("CLSM"), uses a laser beam to image a sample, such as a biopsied tissue sample. In this instrument, the laser beam is focused to a nearly diffraction-limited spot within a single plane of the sample. The spot is then scanned across the plane, or alternatively, the sample is translated using a micrometer stage. In general, the CLSM has greater detection power, superior wavelength selectivity, and better illumination power than the TSCM.